Maybe to help narrow this subject a bit would be to add a qualifier such as: What do you sell and why (in the educational sector, government sector, etc)?
There are so many different cameras for different installs, locations, customer's industry, etc that it would help to know what you're looking for, what's section of the market are you most involved in?
Looking at your questions, specifically: "Is it like comparing a Cadillac to a Ford Fiesta, is the price of the product what compels you to sell other brands?"
I would venture to say some integrators would prefer cameras that have a higher profit margin, so they may push those more than some other brands they sell.
"Can other cameras perform as well if not better for the intended layout?"
Sure they can, some cameras perform better in freezing temperatures, others perform better as pinhole cameras, others are more attractive based on price.
"Does it come down to price not brand name?"
Not necessarily, it depends on the job and using the right camera for the objective it is to meet. For example a PTZ or edge recording camera will likely be more expensive than a camera that does not have those features and an off brand will likely be cheaper than a brand name camera due to their track record and support level.